断层泥蠕变率对地震成核影响的实验研究  

Experimental study of the effect of fault gouge′s creep rate on earthquake nucleation

作　　者：陈浩 陈建业[1] 李子鸿 卓燕群[1] 宋春燕[2] 陈顺云[1] CHEN Hao;CHEN JianYe;LI ZiHong;ZHUO YanQun;SONG ChunYan;CHEN ShunYun(State Key Laboratory of Earthquake Dynamics and Forecasting,Institute of Geology,China Earthquake Administration,Beijing 100029,China;Earthquake Administration of Xinjiang Uygur Autonomous Region,Urumqi 830011,China)

机构地区：[1]中国地震局地质研究所,地震动力学与强震预测全国重点实验室,北京100029 [2]新疆维吾尔自治区地震局,乌鲁木齐830011

出　　处：《地球物理学报》2025年第3期970-987,共18页Chinese Journal of Geophysics

基　　金：中央级公益性科研院所基本科研业务专项(IGCEA2002);国家重点研发计划课题(2021YFC3000603);新疆维吾尔自治区重点研发项目(2020B03006-3)共同资助。

摘　　要：地震发生之前的成核过程受到地震前兆研究的广泛关注,但是断层物质对成核的影响,尤其是与力学行为密切相关的断层泥蠕变率对成核的影响仍不甚清楚.本文使用蠕变率跨越5个数量级的断层泥,开展不同加载速率与正应力下的黏滑实验,探索断层泥蠕变率对成核的影响.结果显示:(1)成核持续时间随着断层泥蠕变率升高而增大,随加载速率升高而缩短;(2)临界成核尺度随蠕变率的升高而增大,随正应力增大而减小;(3)成核扩展速度随蠕变率升高而降低,随加载速率升高而增大;(4)成核位置位于正应力分布低值区;(5)预滑持续时间约为成核持续时间的10倍,是亚失稳持续时间的100倍.上述结果表明,断层泥蠕变率对成核的时间相关量有明显的影响,意味着地震前兆出现的早晚与断层带物质密切相关.并且,成核的出现并不意味着地震立即发生,随之而来的亚失稳阶段对地震短临预测更具现实意义.The nucleation process before an earthquake has received extensive attention in the study of earthquake precursors.However,the influence of fault materials on the nucleation,especially the effect of fault gouge's creep rate closely related to mechanical behavior on nucleation,remains unclear.This paper investigated the effect of fault gouge’s creep rate on laboratory earthquake nucleation using fault gouges with creep rates spanning five orders of magnitude.Stick-slips were generated under different loading rates and normal stresses in experiments.The results indicate that(1)The duration of nucleation increases with increasing creep rate,and decreases with increasing loading rate;(2)The critical nucleation length increases with increasing creep rate,and decreases with increasing normal stress;(3)The propagation velocity of the nucleation decreases with increasing creep rate,and increases with increasing loading rate;(4)The nucleation position is located in the regions of low normal stress;(5)The duration of preslip is approximately ten times the duration of nucleation and one hundred times the duration of meta-instability. The above results indicate that the fault gouge′s creep rate has a significant effect on the temporal properties of nucleation, indicating that the early or late appearance of earthquake precursors is closely related to the fault material. Additionally, earthquakes may not occur immediately even the nucleation process is detected. The meta-instability stage followed is of more practical significance for short-term earthquake prediction.

关 键 词：断层泥蠕变率 地震成核 亚失稳 正应力分布 地震前兆 

分 类 号：P315[天文地球—地震学]